Directive antenna structure



Nov. 28, 1950 w. l.. BARROW ET AL DIRECTIVE ANTENNA STRUCTURE 2 Sheets-Sheet 1 Original Filed Feb. 4, 1942 To H l g h Frequency Apparatus Nov.. z8, 195o Original Filed Feb. 4, 1942 W. L. BARROW ET AL DIRECTIVE ANTENNA STRUCTURE 2 Sheets-Sheet 2 Patented Nov. 28, 1950 DIRECTIVE ANTENNA STRUCTURE Wilmer L. Barrow, Concord, Mass., and Walter W. Mieher, Mineola, N. Y., assignors to The Sperry Corporatioma corporation of Delaware Original application February 4, 1942, Serial No.

429,494. Divided and this application December '7, 1942, Serial No. 468,305

28 Claims.

This invention relates, generally, to the-directional reception or transmission of high frequency electromagnetic energy and the invention more particularly relates to a novel directive antenna structure having a series of differing zones of reception or transmission, said series being repeated in regular sequence. This application is a division of lapplication Serial No. 429,494, led February 4, 1942, led conjointly by the present applicants and Robert J. Marshall.

Heretofore, directive antenna means have been employed for setting up a series of directed zones of transmission or reception, such antenna means comprising a radiating antenna and a cooperating eccentrically mounted parabolic or other ref lector, such reector being rotated to produce the desired space pattern. I'he rotation of these reflectors at high speeds is undesirable owing to the windage and to gyroscopic effects. Furthermore, such reectors are usually supported in large diameter bearings where a wave guide is used to convey the energy to or from the antenna means, such large bearings having but a short life in use and tending to cause overheating and excessive wear of the relatively movable parts.

One object of the present invention is to provide a novel directive antenna structure adapted in use to establish a series of overlapping zones of electromagnetic radiation or reception, said series being repeated indefinitely.

Another object of the present invention is to provide a novel antenna structure comprising a reflector and wave guide means for supplying electromagnetic radiation into said reflector or receiving radiation therefrom.

Still another object of the present invention is to provide a novel directive antenna structure comprising a fixed refiector, wave guide means for conveying energy to or from said reector, and motor-driven deecting means cooperating with the mouth of said wave guide for producing a lobe of electromagnetic radiation or reception whose central axis continuously revolves defining the surface of revolution of a cone. the apex of such surface being centered at the antenna struc# ture.

Another object of the present invention provides a novel antenna structure having a reflector and employing a rectangular wave guide for con veying energy to or from the reector, said wave guide being rotatable with the reflector to produce continuously moving lobes of electromagnetic radiation or reception wherein the polarization changes with the angular movement of the wave guide and reflector.

Other objects and advantages will become apparent from the specification, taken in connection with the accompanying drawings wherein' the invention is embodied in concrete form.

In the drawings, Y

Fig. 1 is a sectional View of an antenna structure embodying principles of the present invention.

Fig. 2 isa view similar to Fig. 1 but of a modied structure.

Fig. 3 is a sectional view taken along the line 3 3 oi Fig. 2.

Fig. 4 is a sectional view taken along the line i-a of Fig. 2. v

Fig. 5 is a detail of a portion of the structure ofv Fig. 2.

Fig. 6 is a fragmentary sectional view of a slight modiication of the structure of Fig. 2.

Figs. 7, 8, 9 and 10 are sectional views showing;

radiated or received energy in two successive positions.

Similar characters of reference are used in all of the above figures to indicate corresponding parts.

' Generally speaking, the invention comprises a reector I of the parabolic type, mounted relative to a wave guide so that electromagnetic waves discharged from the mouth or end of the guide enter the cavity of the parabolic reilector preferably adjacent to its axis. Deflecting means, such as an eccentric nozzle or plate, preferably is rotatable with respect to the reflector axis to provide a movable lobe of electromagnetic energy. However, the reflector also may be made rotatable, either concentric with the axis of rotation or otherwise.

In Fig. l the reflector l is carried by a looped wave guide 32 which has a complementary dummy portion 33 for balancing the rotatable structure shown as being driven by gearing 36, 3l attached to the stub portion Z9 of guide 32. The stub portion communicates with a guide 2,1 extending to the high frequency'transmitter or receiver. Stub portion 29 isshown carried by bearing 3|. It will be noted that mouthA 35 of loop 32 is directed at an angle with respect to the reflector I to give the lobe of electromagnetic reception or transmission, inclination with respect to the axis of rotation as shown in Fig. 11 and thus serves as energy deecting means directing electromagnetic energy between guide 21 or 29 and reflector l. If desired. the reflector l could be tilted instead of the mouth portion 35 and the same result obtained. Reflector l is shown supported from guide means 32, 33 by struts 34.

Thus, where the antenna structure is used as a radiator, energy leaving guide 21 and loop 32 is directed by deector S5 so as to strike the reector E and :then is projected substantially as a lobe such as the Vlobe i1 shown in Fig. 11. As the motor for gears 36 and S1 revolves, this lobe also revolves, its longitudinal axis describing the surface of a right circular cone. On the other hand, if the antenna structure is used as a receiver it will have a revolving zone of electromagnetic reception which at any instant will have the form as shown at i1, but which will revolve as indicated in Fig. 11.

In the structure of Fig. 2, an eccentrically mounted renector 5| and connected wave guide 44 are shown as rotatable. The reflector and guide are shown supported by a tubular member 52 mounted on 'bearings 45 and 45, which tubular member is rotated by gearing 36', 31. The wave guide 44 is rectangular, as shown in Fig. 4, and is coupled to the circular guide portion 29 via a coupling element or rod 39 shown projecting both into the guide 29 and into the portion '38 of. guide 444, the portion 38 extending at rightangles to the circular guide 29 in order to facilitate the transmission yof energy therebetween. In order that the rotation of rectangular guide 44- shall not modulate ythe output of circular guide 29', the electromagnetic energy traversing guide 29 should have a longitudinal electric component. Wave guide portion 38 communi- Cates with the remaining portion of the wave guide portion 44 via off-set portion 42 and a radial portion 43. The rotating circular guide 29 communicates with a stationary circular guide 21. The mouth portion 41 of rectangular guide 44 is shown deiiected so as to extend substantially coaxial With the axis of reflector 5| and is provided with a deiector 49 in the form of a convex curved plate as better shown in Fig. 5, this plate being supported by struts 48 preferably of dielectric material from the mouth portion 41. 49 serves to spread the output of guide i4 substantially uniformly over the walls of reiiector 5| to produce the pattern shown in Fig. y11 as the reflector and antenna structure are revolved.

Owing to the fact that rectangular guide 44 is used and to the fact that the same is revolved, the plane of polarization of the emitted lobe will revolve also. Such plane of polarization will shift in the operation of the structure of Fig. 1 due to the rotation of the member 32.

In Fig. 6 the end portion 41 of the long sides of the guide is shown rounded at 51', preferably about substantially a circular arc to improve the wave front, the radiation striking the flat plate 55' that is shown carried by an insulating box member 53 which plate is just slightly larger than the longer side of the rectangular guide. If desired, this plate could be carried by arms as in Fig, 5. The action of the structure of Fig. 61's very similar to that of Fig. 5.

In Fig. 7 the wave guide 56 is shown as containing a solid dielectric 55 as of polystyrene or other low-loss dielectric. The guide casing or metal Vportion 55 of guide 55-56 terminates in the aperture E@ provided in the reflector 51, which reiiector is mounted rigidly as by struts 58 upon a supporting member 59. The dielectric 55 projects beyond the aperture 55 and is tapered as indicated at 6| and terminates in an inclined metal plate or other deliector 62 that Defleotor is carried by the end of this dielectric tapered portion 6l. The guide 55 is rotatably mounted in a bearing 63. In operation, the guide 56 revolves and energy escapes from the tapered portion 5l of the dielectric in the manner of an end re antenna, and after reflection from the plate 62, strikes the parabolic reiiector 51 to produce a Zone of radiation that revolves with its axis dening the conical surface of a right-cir cular cone as illustrated in Fig. 11.

In this structure of Fig. 8 the parabolic re- `:Elector .E4 has its main axis extending at an angle to the axis of the guide 55-56 and is attached xedly to the guide `casing 56. The tapered portion Sl of the dielectric 55 carries a semi-spherical `reiiector plate 65 at a point to one side of the focus ofreiiector 54. As the reflector 64 and guide 55-56 are revolved within bearing 63, the pattern of Fig. 11 is again produced.

In the structure of Fig. 9 both the axis of the parabolic vreflector 55 and that of the tapered portion 6i of the dielectric 55 are inclined with respect to guide .E5-56. Tapered portion 6|' is shown carrying a reflector plate or deector 61 in the form of a sleeve mounted thereon, and portion 6i projects through this reiiector plate as shown at 58 to produce an end iire array rso that the energy produced by the radiating system has the form shown in Fig. l1, the energy beingsupplied not only from the portion 63 but also reflected by plate 61 and reflector 66.. The degree .of taper of the tapered portion 6| will determine the amount of radiation taking place.

along the taper.

In Fig. 10, portion 6|' is shown tapered .to agreater extent than portie-n 58,' so that the radia-A tion along 5| per unit of length will be greater than that along S8 per lunit .of length. Thus, itis possible to obtain a` lobe having varying intensity of iield throughout its cross-section, such. intensity being controlled at will by the :config-V uration of the tapered portions V6l' and 68.

As many changes could .be made in the abover construction and many apparently widely diier-v ent embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above. description or shown in the accompanying drawings shall be. interpreted as .illustrative and not in a limiting sense.

What is .claimed is:

1,. A directive antenna structure comprising a concave reiiector; -an air-filled metallic conductor having a mouth terminus for conveying electromagnetic energy to or from said reector; and delector means positioned in front of said terminus for transferring energy between said terminus and said reiiector, said terminus, deector and reflector being angulated at an acute angle with respect to the axis of said conductor.

2. A directive antenne. structure comprising a concave reiiector, a hollow wave guide communicating with the concave side of said reflector, said guide being open ended to terminate in a' mouth, deiiector means positioned in front of the mouth of said wave guide and supportedv thereby at an acute angle to the axis of said wave guide for transferring energy between said wave guide and said reflector, said deector means being small compared to said reector,

and means for rotating said deflector means for-r producing a rotating directivity characteristicA for said antenna structure.

3. A directive antenna structure comprising aA concave reflector, a rectangular wave guide comf munioating with the concave side of said reflector, and cylindrical deflector means mechanically coupled to said reflector positioned in front of the mouth of said wave guide and supported thereby for transferring energy between said guide and said reflector and having its axis parallel to one of the sides of said wave guide.

4. A directive antenna structure comprising a reflector, a wave guide for conveying electromagnetic energy to or from said reflector, and energy deflecting means coupling said wave guide to said reflector, said deilecting means being inclined at an acute angle to the axis of said wave guide and separated therefrom for producing a directivity characteristic for said antenna angularly disposed of said axis and being small in size as compared to said reflector.

5. A directive antenna structure comprising a reector, a hollow wave guide for conveying electromagnetic energy, said guide being `open ended to terminate in a mouth, and deflector means separated from and positioned relative to said wave guide at an acute angle to the axis thereof for transferring energy between said wave guide and said reflector, said deflector means being supported by said wave guide and being small in size with respect to said reflector and being rotatable for producing a revolving lobe of electromagnetic energy.

6. A directive antenna structure comprising a reflector, a wave guide for conveying electromagnetic energy to or from said reflector, and electromagnetic energy deflector means supported by said wave guide being small in size as compared to said reflector for transferring energy 1- between said wave guide and said reflector, said deflector means being inclined at a fixed acute angle to the axis of said wave guide and being rotatable about said wave guide axis for producing a revolving electromagnetic energy directivity characteristic.

7. A high frequency directive antenna system comprising, a parabolic reflector, a hollow wave guide* projecting through said reflector substantially at the axis thereof, said guide being open ended to terminate in a mouth, a deflector plate being small in size with respect to said reilector positioned in front of the mouth of said wave guide and inclined at an acute angle relative to said guide, and means for rotating said deflector plate to render said antenna structure successively sensitive to differing zones of electromagnetic reception.

8. In a directive antenna structure comprising, a rotatable wave guide having a looped portion carrying a parabolic reflector, said looped portion having its mouth terminating in front of and extending at an angle with respect to the axis of said reflector, and means for rotating said wave guide.

9. A high frequency directive antenna structure comprising, a parabolic reflector, means for rotating said reilector about an axis extending atan angle to the axis of said reflector, a wave guide rotatable with said reflector and having an emitting portion extending substantially coincident with the axis of said reflector, and a deflector plate positioned in front of said portion of said wave guide supported thereby and rotatable therewith.

10. A high frequency directive antenna structure comprising an axially symmetrical concave reflector, means for rotating said reflector about an axis langularly disposed to the axis of symmetry of said reflector, a wave guide rotatable with said reflector and having an emitting portion extending substantially coincident with the axis of said reflector, and a deflecting plate supported by said wave guide positioned in front of said portion and rotatable therewith.

1l. A high frequency directive antenna structure as defined in claim 5 wherein said wave guide is rectangular, and wherein a circular wave guide is provided communicating with said rectangular wave guide, and coupling means interconnecting said wave guides, said coupling means comprising a rod projecting into both said rectangu lar and circular wave guides.

12. A radiating antenna structure comprising,

a Substantially parabolic reilector, a wave guide projecting through said reilectorsubstantially at the raxis thereof and having an open mouth at the -front of said reflector, and a deflector being small in size compared to said reflector positioned in front of said wave guide mouth and supported thereby so as to transfer energy from said wave guide to said parabolic reflector, said deflector having the form of a flat plate disposed at an acute angle to the axis of said wave guide.

13. A directive antenna system comprising a generally paraboloidal reflector, a wave guide extending through said reflector and communicat-- ing therewith, a deflector member comprising a conduit adjacent to the discharge end of said wave guide and extending at an angle to the axis of said guide, means `for rotating said conduit, and a plate positioned in front of said conduit for transferring energy between said conduit and said paraboloidal reflector.

14. A directive antenna system comprising a concave 'reilecton a wave guide extending through said reflector, land communicating therewith, a deilector means adjacent to and separated from the discharge end of said wave guide and extending at an acute angle to the axis of said guide, said deflector means being small in size compared to said reilector, and means for rotating said deflector means to produce a revolving directivity characteristic for said antenna system.

15. A directive antenna system .comprising a reflector, a Wave guide for conveying electromagnetic energy to or from said reflector, and coupling means between said wave guide and said 1 reflector, said coupling means comprising deilector means separated from said guide being disposed adjacent to said reflector and extending at an acute angle to the axis of said guide, said deector means being small in size compared to said reflector and rotatable for producing la rotating directivity characteristic for said antenna system.

16. A directive antenna structure, comprising a parabolic reflector, a Wave guide for conveying beam of electromagnetic energy, and an energy deflecting member operatively connected between said wave guide and said reector at an acute angle to said wave guide, said deflecting member being small in comparison to said reflector and being supported by said wave guide for recurrently moving through a predetermined path to produce a movable lobe of electromagnetic energy.

17. A directive antenna structure comprising a parabolic reflector adapted to radiate a lobe of radi-ant energy, a wave guide located substantially at the axis of said reflector for conveying electromagnetic energy, and energy deflecting means being small in size compared to said reflector adapted to direct said energy from said wave guide onto said reflector and being sepa- 7. rated from said wave guide, both said reflector and said deflecting means being eccentrically disposed relative to and rotatable about the axis of said wave guide.

18. A directive antenna structure comprising a reflector, a wave guide for conveying electromagnetic energy to or from said reflector, and electromagnetic energy deflecting means separated from said guide adapted to direct electromagnetic energy between said Wave guide and said reflector, said deflecting means being small in size compared to said reflector, both said reflcctor and said deliecting means being disposed at an acute angle relative to and movable relative to the axis of said wave guide.

19. In an antenna structure, a wave guide comprising a hollow conduit adapted to conduct electromagnetic Waves, said guide having a mouth at oneend for discharging said Waves, said conduit having longitudinal walls rounded in convex fashion at said end to improve the wave front of the discharged waves.

20. A directive antenna structure comprising a concave reflector, a rectangular Wave guide having a mouth projecting through said reflector toward the concave side thereof, one opposite pair of sides of said wave guide being rounded at the end of said mouth to improve the Wave front of the waves discharged thereby.

- 21. In an antenna structure, a Wave guide adapted to conduct electromagnetic waves comprising a conduit having -substantially parallel side walls, one pair of said walls being longer than the other pair, whereby the electric lines of force extend transversely of said longer sides, said longer sides being rounded at the discharge end of said guide abouta substantially semi-circular arc to improve the wave front of the discharged waves.

22. A directive antenna structure comprising, a reilector, a holovv rotatable wave guide -for conveying electromagnetic energy, :and deflector means positioned at an acute angle relative to said wave guide and supported thereby for transferring energy between said wave guide and said reflector, said deflector means being small compared to said reflector and said deflector means and said wave guide being rotatable for producing a revolving lobe of electromagnetic energy.

23. A radiating antenna structure comprising, a substantially parabolic reector, a rotatable wave guide projecting through said reiiector substantially at the axis thereof and having an open mouth at the front of said reflector, and a deiiector supported by said guide positioned in front oi said wave guide mouth at an acute angle to the axis of said wave guide, said deector having the form of a semi-cylindrical plate presenting itsvconvex surface towards said wave guide mouth, and being small compared to said reflector.

24. In combination, an air-nlled metallic wave guide having a longitudinal axis and a transverse concave reiiector having an axis, a wave guidesection having an openV end facing said reflector and acutelyangularly disposed relative to the i axis of said reflector, said wave guide section being rotatable to produce a conically rotatable directivity characteristic.

27. High frequency apparatus comprising, a

hollow wave guide of circular crossesection, 'a

rectangular hollow wave guide, said circular cross-section wave guide having an axis intersecting the axis of said rectangular wave guide passing through the interior thereof, and means for intercoupling said wave guides for transfer therebetween of microwave energy, said. coupling means ,comprising a rod extending along the axis of said circular cross-section wave guide and into the interior of said rectangular Wave guide, said rod being terminated in said circular cross-section wave guide.

28. High frequency apparatus as defined in claim 27, wherein said rod is perpendicularv to the parallel Walls of said rectangular wave guide having the greater cross sectional dimensionsr thereof.

WILMER, L. BARROW. WALTER W. MIEHER'.

REFERENCES CITED The following references are of record in thel file of this patent:

UNITED STATES PATENTS Number Name Date 1,931,980 Clavier Oct. 24, 1933 2,083,242 Runge June 8, 1937 2,115,789 Schmid May 3, 1938 2,173,897 Clavier Sept. 26, 1939 2,206,923l Southworth July 9, 1940 2,220,840 Metcalf Nov. 5, 1940 2,255,042 Barrow Sept. 9, 1941 2,342,721 Boerner Feb. 29, 1944 2,370,053 Lindenblad Feb. 20', 1945 FOREIGN PATENTS Number Country Date 841,036 France Jan. 28, 1939 450,484 Great Britain July 20, 1936 OTHER REFERENCES Proceedings of the I. R. E., vol. 27, No. 12, Dey cember 1939, pages 769 and 779. 

